package cn.edu.tju.spider;

import java.util.HashSet;    

/**   
 * 已访问url队列   
 * @author HHZ   
 *   
 */   
public class VisitedUrlQueue    
{    
    public static HashSet<String> visitedUrlQueue = new HashSet<String>();    
   
    public synchronized static void addElem(String url)    
    {    
        visitedUrlQueue.add(url);    
    }    
   
    public synchronized static boolean isContains(String url)    
    {    
        return visitedUrlQueue.contains(url);    
    }    
   
    public synchronized static int size()    
    {    
        return visitedUrlQueue.size();    
    }    
}   
